Bearing configuration for an electronic motor

ABSTRACT

Disclosed is an electronic motor with two bearings. The motor is structured so that, when loaded, the majority of the load (e.g., a radial load) is borne by one of the bearings. The bearing that bears a greater load may be larger and, thus, better suited for a heavy load. In some embodiments, the larger bearing may include rolling elements that have respective radii larger than respective radii of rolling elements of the other bearing by a ratio of at least 1.5 (150%). In some embodiments, the larger bearing may have an outer race with a radius that is greater than a radius of the outer race of the smaller bearing by a ratio of at least 1.5. In some embodiments, the motors may include a third bearing between the two bearings. The third bearing may reduce vibration in the motor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/898,177, filed Feb. 15, 2018, which claims the benefit of U.S.Provisional Application No. 62/555,592, filed Sep. 7, 2017, both ofwhich are incorporated by reference in their entirety.

TECHNICAL FIELD

The disclosure generally relates to the field of electronic motors andin particular to bearing configurations in an electronic motor.

BACKGROUND

Rotational electronic motors (i.e., a motor that drives a rotor torotate about a single axis) are used in a large variety of applications.In an electronic motor, an armature drives a rotor encircled by astator. To minimize friction, the rotor is coupled to the stator and/orother elements of the motor with multiple bearings (e.g.,rolling-element bearings) which allows the rotor to rotate about itsaxis. Bearings generally constrain the rotor from moving in directionsother than rotating about the rotational axis of the motor by bearingaxial loads and/or radial loads.

One such application for electronic motors is in an electronic gimbalthat actively stabilizes the orientation and/or position of a mountedobject (e.g., a camera). Gimbals often include three motors, each tocontrol the orientation of the mounted object along a respective axis ofthree-dimensional space. However, gimbals with more or fewer motors thatthree also are used. In a conventional motor of a gimbal, three bearingscouple to the rotor.

Conventional motors in gimbals generally have two bearings inside themotor and a third bearing outside of the motor. Often, each of thebearings are of similar size. The third bearing outside the motorconnects to the other gimbal arm which is not connected to the motor.Thus, conventional designs have a load path that is supported by twobearings, one in motor and one in gimbal arm.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed embodiments have advantages and features which will bemore readily apparent from the detailed description, the appendedclaims, and the accompanying figures (or drawings). A brief introductionof the figures (FIGS.) is below.

FIG. 1A illustrates a cross-sectional view of a motor with two bearings,in accordance with an example embodiment.

FIG. 1B is a cross-sectional view of an example of a motor with twobearings illustrating load paths through the bearings, in accordancewith an example embodiment.

FIG. 1C illustrates a cross-sectional view of a motor of a motor withthree bearings, in accordance with an example embodiment.

FIG. 2A-2B illustrates a rolling-element bearing, in accordance with anexample embodiment.

FIGS. 3A-3B illustrate a gimbal coupled to a camera in a camera frame,in accordance with some example embodiments.

FIG. 4 is an example of a gimbal and a camera mounted on an aerialvehicle, in accordance with some example embodiments.

FIG. 5 illustrates an example architecture for a camera in accordancewith an example embodiment.

DETAILED DESCRIPTION

The figures and the following description relate to preferredembodiments by way of illustration only. It should be noted that fromthe following discussion, alternative embodiments of the structures andmethods disclosed herein will be readily recognized as viablealternatives that may be employed without departing from the principlesof what is claimed.

Reference will now be made in detail to several embodiments, examples ofwhich are illustrated in the accompanying figures. It is noted thatwherever practicable similar or like reference numbers may be used inthe figures and may indicate similar or like functionality. The figuresdepict embodiments of the disclosed system (or method) for purposes ofillustration only. One skilled in the art will readily recognize fromthe following description that alternative embodiments of the structuresand methods illustrated herein may be employed without departing fromthe principles described herein.

Configuration Overview

Disclosed, by way of example embodiments, is a motor with two bearings.Compared to a conventional motor with three bearings, the two-bearingmotor may be cheaper to manufacture. The two-bearing motor also may bemore reliable (e.g., may be less prone to mechanical breakdown) due todecreased mechanical complexity.

Different types and sizes of bearings differ in the loads which they caneffectively bear. Overloading a bearing may cause the bearing tofunction sub-optimally (e.g., the load may increase the internalfriction of the bearing to an unacceptable degree), shorten the lifetimeof the bearing, and/or cause the bearing to undergo mechanicalbreakdown. The mechanical failure of just one bearing may significantlyincrease the internal friction of the motor. Internal friction may harmthe performance of the motor by, for example, increasing power usage,causing the motor to overheat, slowing the response for the motor,shortening the lifetime of the motor by putting additional strain onother components, and/or decreasing the precision of the motor. Also,mechanical failure of a bearing may cause the elements of the motor tobecome misaligned, which may cause further damage to the motor as themotor continues to operate. Under some conditions, mechanical failure ofa single bearing may make the motor and, by extension, the entire gimbalinoperable. Accordingly, the motor may be designed so that its bearingsare not overloaded.

The two-bearing motor may be more reliable (e.g., less likely to undergomechanical failure or have a longer average lifespan) than aconventional three-bearing motor. This can be because the combinedfailure rate of all three bearings in the three-bearing motor may behigher than the failure rate of the two bearings of the two-bearingmotor. Thus, even in some cases where the individual bearings of thetwo-bearing motor have higher chances of mechanical failure than theindividual bearings of a conventional three-bearing motor, the motorwith the two-bearing motor may still be more reliable than theconventional three-bearing motor.

The two-bearing motor is structured so that, when loaded, the majorityof the load (e.g., a radial load) is borne by one of the bearings. Thebearing that bears a greater load may be larger and, thus, better suitedfor a heavy load. In some embodiments, the larger bearing may includerolling elements that have respective radii larger than respective radiiof rolling elements of the other bearing by a ratio of at least 1.5(150%). In some embodiments, the larger bearing may have an outer racewith a radius that is greater than a radius of the outer race of thesmaller bearing by a ratio of at least 1.5.

In some embodiments, the motor includes three bearings. The motor mayinclude two smaller bearings and one larger bearing, where the largerbearing is the closest bearing to the load of the motor. The thirdbearing may reduce vibration in the motor. In some embodiments, theaddition of the third bearing decreases the length of standing waves onthe rotor of the motor, thereby increasing the frequency of thefundamental harmonic of the motor.

Example Aerial Vehicle Configuration

FIG. 1A illustrates a cross-sectional view of a motor with two bearings,in accordance with an example embodiment. The motor 100 may be abrushless electronic motor with a rotating component and a fixedcomponent. The fixed component of the motor 100 may include a firstmotor shell 110, a stator 130, one or more screws 160, and a mount 150.The elements of the fixed component may be mutually coupled together soas to rotate together as a single rigid (or approximately rigid)element. The rotating component of the motor 100 may include a rotor140, a rotor screw 145, and a second motor shell 120. The elements ofthe rotating component may also be mutually coupled together, and therotating component and the fixed component may rotate relative to eachother along an axis of rotation. A first bearing 170A and a secondbearing 170B may couple the rotating component to the fixed componentand allow the rotating component to rotate relative to the fixedcomponent.

The first motor shell 110 and the second motor shell 120 enclose orpartially enclose elements of the motor 100 including the stator 130,the first bearing 170A, the second bearings 170B, and at least a portionof the rotor 140. The first motor shell 110 and second motor shell 120may be, for example, plastic, metal, or ceramic. The first motor shell110 and second motor shell 120 may together form a seal or a partialseal to prevent particles (e.g., dust or sand) or liquids from enteringthe internal components of the motor 100. The outer surfaces of thefirst motor shell 110 and the second motor shell 120 may beapproximately flush.

The stator 130 and the rotor 140 interoperate together as a rotarysystem to rotate the rotor 140. The stator 130 may be stationary and therotor 140 may rotate when power is supplied to the motor 100. One of thestator 130 and the rotor 140 may be an armature of the motor 100 and theother may be a field magnet. The stator 130, the rotor 140, or both mayinclude one or more electromagnets and/or one or more permanent magnets.Electric power (e.g., direct current (DC) power, single-phasealternating current (AC) power, or three-phase power) may be supplied tothe armature of the motor 100 to rotate the rotor 140.

The rotor 140 is driven to rotate the rest of the rotating component ofthe motor 100. The rotor 140 may couple to the rotating component (e.g.,to the second motor shell 120) with a mechanical fastener, such as therotor screw 145 illustrated in FIG. 1A. The rotor screw 145 mayrotationally couple the rotor 140 to the second motor shell 120. In someembodiments, the rotor 140 and the rotating component (e.g., the secondmotor shell 120) may be coupled together with one or more alternatemechanical fasteners (e.g., screws, bolts, nails, staples, or pins).Also, instead of or in addition to mechanical fasteners, the rotor 140and the second motor shell 120 may be coupled together with anothercoupling means, such as an adhesive (e.g., liquid adhesive, resins,acid-based cements, adhesive tape, or some combination thereof) orthermal bonding (e.g., welding).

The mount 150 may be a rigid element that couples various elements ofthe motor 100 together. The mount 150 may couple to the stator 130, thefirst bearing 170A, the second bearing 170B, and the first motor shell110. The mount 150 may be composed of a rigid material, such as aplastic with a high Young's modulus.

The one or more screws 160 (one of which is illustrated in FIG. 1A)couple the first motor shell 110 to the mount 150. Instead of or inaddition to the one or more screws 160, the first motor shell 110 may becoupled to the mount 150 with alternate mechanical fasteners, adhesive,or thermal bonding.

The first bearing 170A and the second bearing 170B (referred to hereincollectively as “bearings 170”) are rotational bearings that allow therotating component of the motor 100 to rotate relative to the fixedcomponent. The second bearing 170B may be larger than the first bearing170A and may be rated for a larger load. The bearings 170 may berolling-element bearings, such as ball bearings (e.g., a deep-grooveradial ball bearing) or roller bearings (e.g., cylindrical rollerbearings, spherical roller bearings, needle roller bearings, taperedroller bearings, gear bearings, or toroidal bearings). In someembodiments, the first bearing 170A is a different type of bearing thanthe second bearing 170B. For example, one of the bearings 170 (e.g., thesecond bearing 170B) may be a bearing that locates axially (e.g., adeep-groove radial ball bearing) and the other bearing 170 (e.g., thefirst bearing 170A) may be a bearing that does not locate axially (e.g.,a cylindrical roller bearing).

The motor 100 may include additional elements not illustrated in FIG.1A. For example, the motor 100 may detect the position (angle) of therotor 140 with an electro-mechanical position detection device, such asa rotary encoder (e.g., an absolute encoder and/or an incrementalencoder), a magnetic encoder, or a resistive potentiometer. The positiondetection device may output a digital or analog signal that indicatesthe position of the rotor 140.

The motor 100 also may include circuitry for receiving instructions andfor controlling and driving the motor 100. This circuitry may beembodied on one or more integrated circuits (ICs). The instructions maybe received from external control logic (e.g., transmitted by a wire).The instructions may, for example, establish a setpoint for the positionof the rotor 140. The circuitry for controlling the motor 100 mayinclude a proportional-integral-differential (PID) controller or aproportional-summation-difference (PSD) controller that controls theposition of the rotor 140 based on the output of the position detectiondevice. The circuitry for driving the motor 100 may provide power to thearmature of the motor 100 based on the output of the control circuitry.In addition, an end bell (or motor magnet holder) 172 couples a shaftwith a magnetic ring, while mount 150 couples with the stator. Whenenergized, the motor and stator rotate to operate the motor 100.

The motor 100 illustrated in FIG. 1A may be part of a gimbal. Inalternate embodiments, the motor 100 may be part of other motor movementsystems. The fixed component of the motor 100 may couple to a baseobject, such as the first arm segment 180 and elements coupled thereto(e.g., an aerial vehicle to which the gimbal couples). The rotatingcomponent of the motor 100 may couple to a rotating load object, suchas, a second arm segment (not illustrated in FIG. 1A) of the gimbal andelements coupled thereto (e.g., a camera coupled to the gimbal). A forceon the rotating load object (e.g., gravity, wind, or any other force) isdistributed through the motor 100 into the base object. Forces on therotating load object, thus produce a load on the motor 100.

The motor 100 may be subject to axial loads (e.g., a load in thedirection of the axis of the rotor 140) and radial loads (e.g., a loadperpendicular to the axis of the rotor 140). A radial load may resultfrom forces (e.g., gravity) on the rotating load object coupled to therotor 140 and from the inertia of the rotating load object when the baseobject undergoes angular or linear acceleration. The radial load istransferred from the rotor 140 to the rotating component of the motor100 through the bearings 170 and through the mount 150. A radial load onthe motor 100 thus produces a load on the bearings 170. The geometry ofthe motor 100 may be such that the load on the second bearing 170B froma radial load is significantly greater than the load on the firstbearing 170A. Because it is not required to bear as great of a load, thefirst bearing 170A may be smaller than the second bearing 170B.

FIG. 1B is a cross-sectional view of an example of a motor 100 with twobearings illustrating load paths through the bearings, in accordancewith an example embodiment. FIG. 1B illustrates four load paths throughthe motor 100 corresponding to a radial load on the rotor 140: the firstload path 190A, the second load path 190B, third load path 190C, and thefourth load path 190D (collectively referred to herein as “load paths190”). A load path 190 is a path through elements that bear a load. Theload path 190 represents the transfer of mechanical stress betweenelements in the motor 100. Each of the load paths 190 shown in FIG. 1Billustrates mechanical stress being distributed from the rotor screw 145into the fixed component of the motor 100 through either the firstbearing 170A or the second bearing 170B.

The motor 100 may be configured so that the stator 130 and the firstbearing 170A are “floating” with respect to the rest of the fixedcomponent of the motor 100. That is, in some embodiments, the firstbearing 170A and the stator 130 do not connect to any component of themotor 100 other than the mount 150 and the path from the first bearing170A and the stator 130 through the mount 150 to the rest of the fixedcomponent of the motor 100 is relatively indirect.

Thus, load paths 190 that pass through the second bearing 170B (e.g.,the first load path 190A and the second load path 190B) are shorter thanthe load paths 190 that pass through the first bearing 170A (e.g., thethird load path 190A and the fourth load path 190B). Because the loadpaths 190 that pass through the second bearing 170B are shorter than theload paths 190 that pass through the first bearing 170A, when the twobearings 170 are loaded equally, the resultant strain (i.e.,deformation) on the mount 150 is smaller along the paths through thesecond bearing 170B (e.g., along the first load path 190A and the secondload path 190B) than along the paths through the first bearing 170A. Asa consequence, the load borne by the first bearing 170A is significantlyless than that borne by the second bearing 170B.

FIG. 1C illustrates a cross-sectional view of a motor with threebearings, in accordance with an example embodiment. The motor 100 shownin FIG. 1C may be configured similarly to the motor 100 of FIG. 1A. Thefirst bearing 170A and the second bearing 170B of the motor 100illustrated in FIG. 1A may correspond to the first bearing 170A and thesecond bearing 170B of the motor 100 in FIG. 1C. However, the motor 100of FIG. 1C also includes an additional third bearing 170C.

The third bearing 170C may be located in between the first bearing 170Band the second bearing 170B. Like the first bearing 170A and the secondbearing 170B, the third bearing may encircle the rotor 140 and couplethe rotor 140 to the mount 150. The third bearing 170C may be similar insize to the first bearing 170A and may be smaller than the secondbearing 170B. The third bearing 170C may bear less load than the secondbearing 170B. The third bearing 170C may reduce vibration in the motor100. In some embodiments, the addition of the third bearing 170Cdecreases the length of standing waves on the rotor 140, therebyincreasing the frequency of the fundamental harmonic of the motor 100.This configuration also may provide a stiffer joint, which may help withcontrol systems.

FIGS. 2A and 2B illustrate a bearing 170, in accordance with an exampleembodiment. FIG. 2A illustrates a cross-sectional view of the bearing170 and FIG. 2B illustrates a portion of the bearing 170 from a viewalong the axis of the bearing 170. The bearing 170 includes an innerrace 210, an outer race 220, and multiple rolling elements 230.

The inner race 210 encircles and couples to the rotor 140 of the motor100 and the outer race 220 couples to the mount 150 and/or the stator130. The inner race 210 and outer race 220 may be composed, partially orentirely, of metal (e.g., stainless steel or chrome steel) or ceramic(e.g., silicon nitride). The inner race 210 and outer race 220 mayinclude respective grooves which the rolling elements 230 traverse. Theinner race 210 and the outer race 220 may be concentric and may rotatewith respect to each other.

The rolling elements 230 illustrated in FIGS. 2A and 2B may be sphericalballs. In alternate embodiments, the rolling elements 230 may beellipsoidal elements, cylindrical elements, tapered rollers, needlerollers, or elements of another shape that is approximately symmetricabout an axis rotation. The rolling elements 230 may be composed,partially or entirely, of metal (e.g., stainless steel or chrome steel),ceramic (e.g., silicon nitride or aluminum oxide), plastic (e.g.,polyoxymethylene, polyvinyl chloride, or Nylon), or any other suitablematerial. The rolling elements 230 may have a smooth texture wherereduced friction is desired. If for any reason friction is desired, therolling elements 230 may have a rougher texture.

In some embodiments, the bearing 170 may include a cage that maintainsthe distance between each of the rolling elements 230. The cage mayreduce friction in the bearing 170 by preventing the rolling elementsfrom coming into contact with one another. The bearing 170 may alsoinclude lubricant to further reduce friction. The embodiment of thebearing 170 illustrated in FIGS. 2A and 2B is a single-row ball bearing,but in alternate embodiments the bearing 170 may include multiple rows.That is, the bearing 170 may include two or more grooves on the innerrace 210, a respective groove on the outer race 210 for each of thegrooves of the inner race 210, and a set of rolling elements 230corresponding to each pair of grooves.

FIGS. 2A and 2B illustrate the axis of the bearing 240. The axis of thebearing 240 is the axis of rotation for the rotor 140 and may be theaxis of the inner race 210 and of the outer race 220. The rollingelements 230 may lie in a plane orthogonal to the axis of the bearing240. Each of the rolling elements 230 may be equidistant from the axisof the bearing 240.

Herein, the inner race radius 260 may refer to the minimum distancebetween the surface of the inner race 210 that a rolling element 230 isin contact with and the axis of the bearing 240. For example, in theembodiment illustrated in FIG. 2A, the inner race radius 260 is thedistance between the trough of the groove of the inner race 210 and theaxis of the bearing 240.

The rolling element radius 250 denotes half of the largest extension ofa rolling element 230 perpendicular to the axis about which it rolls.For example, if a bearing 170 is a ball bearing or cylindrical rollerbearing, the rolling element radius 250 is simply the radius of one ofthe rolling elements 230 (e.g., the radius of the ball bearings or theradius of the cylindrical rolling elements). As another example, if thebearing 170 is a toroidal bearing, the rolling element radius 250 is theradius of the largest circular cross section of the rolling elements230.

The outer race radius 270 refers to the maximum length of a distancevector between the surface of the outer race 220 that a rolling element230 is in contact with and the axis of the bearing 240, where the vectoris perpendicular to the axis of the bearing. For example, in a ballbearing with grooves, as illustrated in FIGS. 2A-2B, the outer raceradius 270 may be the trough of the groove of the outer race 220. Theouter race radius 270 may be slightly longer than the sum of the innerrace radius 260 and the diameter of the rolling elements 230 (i.e.,twice the rolling element radius 250).

Returning now to FIG. 1A, the first bearing 170A may be smaller than thesecond bearing 170B. The rolling elements 230 of the second bearing 170Bmay have respective radii larger than the respective radii of therolling elements 230 of the first bearing 170A by a ratio of at least1.5 (150%). Also, the radius of the outer race 220 of the second bearing170B may be greater than the radius of the outer race 220 of the firstbearing 170A by a ratio of at least 1.5.

Because the second bearing 170B is larger than the first bearing 170A,the second bearing 170B may be capable of bearing a greater load thanthe first bearing 170A. Thus, the motor 100 may be structured so thatthe majority of the load is borne by the second bearing 170B, withoutbeing unacceptably prone to bearing failure.

Returning now to FIG. 1C, the third bearing 170C may be smaller thansecond bearing 170B and of similar size to the first bearing 170A. Thethird bearing 170C may include rolling elements 230, and the respectiveradii of the rolling elements 230 of the second bearing 170B may belarger than respective radii of the rolling elements 230 of the thirdbearing 170C by a ratio of 1.5 or more. The rolling elements 230 of thethird bearing 170C may be of similar size to the rolling elements 230 ofthe first bearing 170A. For example, the radii of the rolling elements230 third bearing 170C and the radii of the radii of the rollingelements 230 first bearing 170A may differ by a factor of 0.1 or less.In some embodiments, the outer race radius 270 of the second bearing170B is greater than the outer race radius 270 of the third bearing 170Cby a ratio of at least 1.5. The outer race radii 270 of the firstbearing 170A and the third bearing 170C may differ by a factor of 0.1 orless.

Example Gimbal

FIGS. 3A and 3B illustrate an example embodiment of a gimbal 300attached to a camera frame 355, which itself is attached to a camera350. The example gimbal 300 includes a base arm 320, a middle arm 330, amount arm 340, a first motor 310A, a second motor 310B, and a thirdmotor 310C. The first motor 310A, the second motor 310B, and the thirdmotor 310C are collectively referred to herein as motors 310. Some orall of the motors 310 may be structured like the motors 100 illustratedin FIGS. 1A and/or 1C.

The base arm 320 may include a mechanical attachment portion 370 at afirst end of the base arm 320 that allows the gimbal 300 to securelyattach to a reciprocal component on a mount platform (e.g., an aerialvehicle, a ground vehicle, or a handheld grip), and also be removable.The base arm 320, the middle arm 330, and the mount arm 340 may includethe first motor 310A, the second motor 310B, and the third motor 310C,respectively. The first motor 310A may be at a second end of the basearm 320 and may couple to the first end of the middle arm 330.Similarly, the second motor 310B may be at a second end of the middlearm 330 and may couple to the first end of the mount arm 330. The secondend of the mount arm 330 includes the third motor 310C which mayremovably couple to the camera frame 355. The camera frame 355 mayremovably couple to (e.g., partially enclose) the camera 350.

The gimbal 300 may be configured to allow for rotation of a mountedobject in space. In the embodiment depicted in FIGS. 3A and 3B, themounted object is a camera 350 to which the gimbal 300 is mechanicallycoupled. The gimbal 300 may allow for the camera 350 to maintain aparticular orientation in space so that it remains relatively steady asthe mount platform to which it is attached moves (e.g., as an aerialvehicle tilts or turns during flight). The gimbal 300 may have threemotors 310, each of which rotates the mounted object (e.g., the camera350) about a specific axis of rotation. Herein, for ease of discussion,the motors 310 are numbered by their proximity to the mount platform(i.e., the first motor 310A, the second motor 310B, and the third motor310C).

The gimbal 300 may include a gimbal control system that controls theorientations of each of the motors 310. In some embodiments, the gimbalcontrol system is part of a mount platform to which the gimbal 300couples. In some embodiments, the gimbal control system may includeinteroperating components on both the mount platform and the gimbal 300.

A sensor system of the gimbal 300 may detect the current orientation ofthe mounted with a sensor unit that may include rotary encoders for themotors 310, an inertial measurement unit (IMU), a digital compass, orsome combination thereof. After detecting the current orientation of themounted object, via a sensor unit, the gimbal control system maydetermine a preferred orientation along each of the three axes ofrotation (e.g., yaw, pitch, and roll). The preferred orientation may beused by the gimbal control system to compute a rotation for each motor310 in order to move the camera 350 to the preferred orientation or keepthe camera 350 in the preferred orientation.

The axis to which each motor 310 corresponds may depend on the mountplatform to which the gimbal 300 is attached. For example, when attachedto an aerial vehicle, the first motor 310A may rotate the mounted objectabout the roll axis, the second motor 310B may rotate corresponding torotation in yaw, and the third motor 310C may correspond to rotation inpitch. However, when the same gimbal 300 is attached to a handheld grip,the motors 310 may correspond to different axes: for example, the firstmotor 310A corresponds to yaw, and the second motor 310B corresponds toroll, while the third motor 310C still corresponds to pitch.

In one embodiment, each of the three motors 310 is associated with anorthogonal axis of rotation. However, in some embodiments, such as theembodiment depicted in FIG. 3A and FIG. 3B the motors 310 of the gimbal300 are not orthogonal. A gimbal 300 in which the motors 310 are notorthogonal may have at least one motor 310 that rotates the mountedobject about an axis which is not orthogonal to the axis of rotation ofthe other motors 310. A non-orthogonal motor 310 configuration of thegimbal 300 may allow for a larger range of unobstructed viewing anglesfor the camera 350. For example, in the embodiment shown in FIGS. 3A and3B, the pitch of the camera 350 relative to the connection of the gimbal300 to the mount platform (e.g., an aerial vehicle) can be about 16°higher without the field of view of the camera 350 being obstructed(i.e., without the second motor 310B appearing in the image captured bythe camera 350) than it could with an orthogonal motor configuration. Insome embodiments, the second motor 310B is not identical to the othertwo motors 310A, 310C. The second motor 310B may be capable of producinga higher torque than the other two motors 310A, 310C.

The gimbal 300 also may couple mechanically to a mount platform via amechanical attachment portion 370. The mechanical attachment portion 370may be part of the base arm 320. The mechanical attachment portion 370may include a mechanical locking mechanism to securely attach to areciprocal component on a mount platform (e.g., an aerial vehicle, aground vehicle, an underwater vehicle, or a handheld grip). The examplemechanical locking mechanism shown in FIGS. 3A and 3B includes a groovewith a channel in which a key (e.g., a tapered pin or block) on areciprocal component on a mount platform can fit. The gimbal 300 can belocked with the mount platform in a first position and unlocked in asecond position, allowing for detachment of the gimbal 300 from themount platform. The mechanical attachment portion 370 may connect to areciprocal component on a mount platform in which the mechanicalattachment portion 370 is configured as a female portion of a sleevecoupling and in which the mount platform is configured as a male portionof a sleeve coupling.

In some embodiments, the gimbal 300 includes a mount connector 380 whichallows the gimbal 300 to electronically couple to a mount platform. Themount connector 380 may include a power connection which provides powerfrom the mount platform to the gimbal 300 and/or the camera 350. Themount connector 380 may also allow communication between the gimbal 300and the mount platform. In some embodiments, the mount connector 380connects to the camera 350 via one or more data busses which allowcommunication between the mount platform and the camera 350. The gimbal300 may include an internal bus which connects between the camera frame355 and the mount connector 380 and allows for communication between themount platform and the camera 350.

The camera 350 may be enclosed or mounted to a camera frame 355. Thecamera frame 355 may include electronic connectors which can couple withthe corresponding camera 350. The camera frame 355 may include, forexample, a micro USB connector, which can provide power to the camera350 and can allow the mount platform (e.g., an aerial vehicle) to sendexecutable instructions to the camera 350, such as a command to changethe frame rate of a video, or take a picture. The camera frame 355 mayalso include a video interface connector (e.g., a High-DefinitionMultimedia Interface (HDMI) connector), which may allow the camera totransmit captured video, audio, and images to the mount platform. Thecamera frame 355 may include any set of connectors and utilize anycommunication protocols to transmit data to and from the mount platform.The camera frame 355 may include a set of connectors which connect tothe gimbal 300, so that the gimbal 300 can act as a bus for transmittingdata or power between the mount platform and the camera 350, and viceversa.

Example Aerial Vehicle

FIG. 4 is an example of a gimbal and a camera mounted on an aerialvehicle, in accordance with some embodiments. The aerial vehicle 400 inthis example is shown with a housing 410 and four arms 420. The housing410 may enclose a payload (e.g., electronics, storage media, and/orcamera). A thrust motor 430 may be coupled with the end of each arm 420,and a respective propeller 440 may be coupled to each thrust motor 430.The thrust motors 430 may spin the propellers 440 when the thrust motors430 are operational. When the thrust motors 430 are operational, all thepropellers 440 may spin at appropriate speeds to allow the aerialvehicle 400 to lift (take off), land, hover, move (e.g., forward,backward), and rotate in flight. Modulation of the power supplied toeach of the thrust motors 430 may control the trajectory and torque onthe aerial vehicle 400. The aerial vehicle 400 may be coupled to agimbal 300, a camera frame 355, and a camera 350.

The gimbal 300 may be coupled to the housing 410 of the aerial vehicle400 through a removable coupling mechanism that mates with a reciprocalmechanism on the aerial vehicle 400 having mechanical and communicativecapabilities. In some embodiments, the gimbal 300 may be attached orremoved from the aerial vehicle 400 without the use of tools. The gimbal300 may control the position and/or orientation of the camera 350.

Example Camera Architecture

FIG. 5 illustrates a block diagram of an example camera architecture.The camera architecture 505 corresponds to an architecture for a camera,e.g., camera 350. In one embodiment, the camera 350 is capable ofcapturing spherical or substantially spherical content. As used herein,spherical content may include still images or video having spherical orsubstantially spherical field of view. For example, in one embodiment,the camera 350 captures video having a 360° field of view in thehorizontal plane and a 180° field of view in the vertical plane.Alternatively, the camera 350 may capture substantially spherical imagesor video having less than 360° in the horizontal direction and less than180° in the vertical direction (e.g., within 10% of the field of viewassociated with fully spherical content). In other embodiments, thecamera 350 may capture images or video having a non-spherical wide anglefield of view.

As described in greater detail below, the camera 350 may include sensors540 to capture metadata associated with video data, such as timing data,motion data, speed data, acceleration data, altitude data, GPS data, andthe like. In a particular embodiment, location and/or time centricmetadata (geographic location, time, speed, etc.) can be incorporatedinto a media file together with the captured content in order to trackthe location of the camera 350 over time. This metadata may be capturedby the camera 350 itself or by another device (e.g., a mobile phone orthe aerial vehicle 400) proximate to the camera 350. In one embodiment,the metadata may be incorporated with the content stream by the camera350 as the content is being captured. In another embodiment, a metadatafile separate from the video file may be captured (by the same capturedevice or a different capture device) and the two separate files can becombined or otherwise processed together in post-processing. Thesesensors 540 can be in addition to sensors in a telemetric subsystem ofthe aerial vehicle 400. In embodiments in which the camera 350 isintegrated with the aerial vehicle 400, the camera need not haveseparate individual sensors, but rather could rely upon the sensorsintegrated with the aerial vehicle 400.

In the embodiment illustrated in FIG. 5 , the camera 350 includes acamera core 510 comprising a lens 512, an image sensor 514, and an imageprocessor 515. The camera 350 additionally includes a system controller520 (e.g., a microcontroller or microprocessor) that controls theoperation and functionality of the camera 350 and system memory 530configured to store executable computer instructions that, when executedby the system controller 520 and/or the image processors 515, performthe camera functionalities described herein. In some embodiments, acamera 350 may include multiple camera cores 510 to capture fields ofview in different directions which may then be stitched together to forma cohesive image. For example, in an embodiment of a spherical camerasystem, the camera 350 may include two camera cores 510 each having ahemispherical or hyper hemispherical lens that each captures ahemispherical or hyper hemispherical field of view which are stitchedtogether in post-processing to form a spherical image.

The lens 512 can be, for example, a wide angle lens, hemispherical, orhyper hemispherical lens that focuses light entering the lens to theimage sensor 514 which captures images and/or video frames. The imagesensor 514 may capture high-definition images having a resolution of,for example, 720p, 1080p, 4 k, or higher. In one embodiment, sphericalvideo is captured in a resolution of 5760 pixels by 2880 pixels with a360° horizontal field of view and a 180° vertical field of view. Forvideo, the image sensor 514 may capture video at frame rates of, forexample, 30 frames per second, 60 frames per second, or higher. Theimage processor 515 performs one or more image processing functions ofthe captured images or video. For example, the image processor 515 mayperform a Bayer transformation, demosaicing, noise reduction, imagesharpening, image stabilization, rolling shutter artifact reduction,color space conversion, compression, or other in-camera processingfunctions. Processed images and video may be temporarily or persistentlystored to system memory 530 and/or to a non-volatile storage, which maybe in the form of internal storage or an external memory card.

An input/output (I/O) interface 560 may transmit and receive data fromvarious external devices. For example, the I/O interface 560 mayfacilitate the receiving or transmitting video or audio informationthrough an I/O port. Examples of I/O ports or interfaces include USBports, HDMI ports, Ethernet ports, audio ports, and the like.Furthermore, embodiments of the I/O interface 560 may include wirelessports that can accommodate wireless connections. Examples of wirelessports include Bluetooth, Wireless USB, Near Field Communication (NFC),and the like. The I/O interface 560 may also include an interface tosynchronize the camera 350 with other cameras or with other externaldevices, such as a remote control, a second camera, a smartphone, aclient device, or a video server.

A control/display subsystem 570 may include various control and displaycomponents associated with operation of the camera 350 including, forexample, LED lights, a display, buttons, microphones, speakers, and thelike. The audio subsystem 550 may include, for example, one or moremicrophones and one or more audio processors to capture and processaudio data correlated with video capture. In one embodiment, the audiosubsystem 550 may include a microphone array having two or microphonesarranged to obtain directional audio signals.

The sensors 540 may capture various metadata concurrently with, orseparately from, video capture. For example, the sensors 540 may capturetime-stamped location information based on a global positioning system(GPS) sensor, and/or an altimeter. Other sensors 540 may be used todetect and capture orientation of the camera 350 including, for example,an orientation sensor, an accelerometer, a gyroscope, or a magnetometer.Sensor data captured from the various sensors 540 may be processed togenerate other types of metadata. For example, sensor data from theaccelerometer may be used to generate motion metadata, comprisingvelocity and/or acceleration vectors representative of motion of thecamera 350. Furthermore, sensor data from the aerial vehicle 400 and/orthe gimbal 300 may be used to generate orientation metadata describingthe orientation of the camera 350. Sensor data from a GPS sensor canprovide GPS coordinates identifying the location of the camera 350, andthe altimeter can measure the altitude of the camera 350. In oneembodiment, the sensors 540 are rigidly coupled to the camera 350 suchthat any motion, orientation or change in location experienced by thecamera 350 is also experienced by the sensors 540. The sensors 540furthermore may associates a time stamp representing when the data wascaptured by each sensor. In one embodiment, the sensors 540automatically begin collecting sensor metadata when the camera 350begins recording a video.

Additional Considerations

The disclosed configuration describes an electronic motor with twobearings. The motor may be structured so that, when loaded, the majorityof the load (e.g., a radial load) is borne by one of the bearings. Thebearing that bears a greater load may be larger and, thus, better suitedfor a heavy load. In some embodiments, the larger bearing may includerolling elements that have respective radii larger than respective radiiof rolling elements of the other bearing by a ratio of at least 1.5(150%). In some embodiments, the larger bearing may have an outer racewith a radius that is greater than a radius of the outer race of thesmaller bearing by a ratio of at least 1.5. In some embodiments, themotors may include a third bearing between the two bearings. The thirdbearing may reduce vibration in the motor. Further, the disclosedconfiguration increases gimbal reliability, increases mounting optionson the shaft, reduces weight, and provides stiffer joints, which mayfurther assist with stability and higher resonance for control system.

Throughout this specification, plural instances may implementcomponents, operations, or structures described as a single instance.Although individual operations of one or more methods are illustratedand described as separate operations, one or more of the individualoperations may be performed concurrently, and nothing requires that theoperations be performed in the order illustrated. Structures andfunctionality presented as separate components in example configurationsmay be implemented as a combined structure or component. Similarly,structures and functionality presented as a single component may beimplemented as separate components. These and other variations,modifications, additions, and improvements fall within the scope of thesubject matter herein.

Unless specifically stated otherwise, discussions herein using wordssuch as “processing,” “computing,” “calculating,” “determining,”“presenting,” “displaying,” or the like may refer to actions orprocesses of a machine (e.g., a computer) that manipulates or transformsdata represented as physical (e.g., electronic, magnetic, or optical)quantities within one or more memories (e.g., volatile memory,non-volatile memory, or a combination thereof), registers, or othermachine components that receive, store, transmit, or displayinformation.

As used herein any reference to “one embodiment” or “an embodiment”means that a particular element, feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment.

Some embodiments may be described using the expression “coupled” and“connected” along with their derivatives. For example, some embodimentsmay be described using the term “coupled” to indicate that two or moreelements are in direct physical or electrical contact. The term“coupled,” however, may also mean that two or more elements are not indirect contact with each other, but yet still co-operate or interactwith each other. The embodiments are not limited in this context.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

In addition, use of the “a” or “an” are employed to describe elementsand components of the embodiments herein. This is done merely forconvenience and to give a general sense of the invention. Thisdescription should be read to include one or at least one and thesingular also includes the plural unless it is obvious that it is meantotherwise.

Upon reading this disclosure, those of skill in the art will appreciatestill additional alternative structural and functional designs for thedisclosed motor. Thus, while particular embodiments and applicationshave been illustrated and described, it is to be understood that thedisclosed embodiments are not limited to the precise construction andcomponents disclosed herein. Various modifications, changes andvariations, which will be apparent to those skilled in the art, may bemade in the arrangement, operation and details of the method andapparatus disclosed herein without departing from the spirit and scopedefined in the appended claims.

What is claimed is:
 1. An electronic motor comprising: a rotor; a mount;a stator extending around a portion of the mount; a first bearingencircling the rotor and coupling the rotor to the stator, the firstbearing including a first plurality of rolling elements, the firstbearing being directly connected with the stator at a first outer raceof the first bearing and directly connected to the rotor at a firstinner race of the bearing so that the rotor is movable relative to thestator, and the first bearing being co-axial with the mount and beingaxially spaced apart from the mount; a second bearing encircling therotor and directly coupling the rotor to the mount, the second bearingincluding a second plurality of rolling elements; a top shell enclosingthe first bearing, the top shell being configured to couple to an aerialvehicle arm at a first side and being configured to couple to the mountat a second side opposite the first side; and a bottom shell enclosingthe second bearing, the bottom shell being configured to couple to therotor.
 2. The electronic motor of claim 1, wherein the second pluralityof rolling elements have respective radii larger than respective radiiof the first plurality of rolling elements.
 3. The electronic motor ofclaim 1, wherein the top shell is fixed and the bottom shell isrotatable.
 4. The electronic motor of claim 1, wherein the top shell isconfigured to couple to a top surface of the aerial vehicle arm.
 5. Theelectronic motor of claim 1, wherein the top shell is configured tocouple to the mount at the second side opposite the first side via afirst fastening mechanism through a bottom surface of the top shell. 6.The electronic motor of claim 1, wherein the aerial vehicle arm includesa bottom surface extending into the electronic motor and beingconfigured to couple to a bottom surface of the mount at the first side.7. The electronic motor of claim 1, wherein the bottom shell isconfigured to couple to the rotor via a second fastening mechanismthrough a bottom surface of the bottom shell.
 8. The electronic motor ofclaim 1, wherein: the first bearing comprises: the first inner race thatencircles the rotor; and the first outer race that couples to thestator, wherein each of the first plurality of rolling elements is incontact with the first inner race and the first outer race, and thesecond bearing comprises: a second inner race that encircles and couplesto the rotor; and a second outer race that couples directly to themount, wherein each of the second plurality of rolling elements is incontact with the second inner race and the second outer race.
 9. Theelectronic motor of claim 1, wherein each of the first and the secondplurality of rolling elements is any of a spherical ball and acylindrical element.
 10. The electronic motor of claim 1, furthercomprising: a third bearing encircling the rotor and coupling the rotorto the mount, the third bearing being configured between the firstbearing and the second bearing.
 11. The electronic motor of claim 10,wherein the third bearing includes a third plurality of rollingelements, and wherein the second plurality of rolling elements haverespective radii larger than respective radii of the third plurality ofrolling elements.
 12. The electronic motor of claim 11, wherein thethird bearing comprises: an inner race that encircles and couples to therotor; and an outer race that couples to the mount, wherein each of thethird plurality of rolling elements is in contact with the inner raceand the outer race.
 13. The electronic motor of claim 10, wherein thethird bearing includes a third plurality of rolling elements, andwherein first plurality of rolling elements have respective radii thatdiffer from the respective radii of the third plurality of rollingelements.
 14. The electronic motor of claim 1, wherein the rotor isencircled by no bearings other than the first and second bearings. 15.The electronic motor of claim 1, wherein the second bearing is notencircled by the stator.
 16. The electronic motor of claim 1, whereinthe top shell couples to the mount and partially encloses the stator,the first and second bearings, and at least a portion of the rotor. 17.An aerial vehicle motor comprising: a first bearing located along anaxis that extends through the aerial vehicle motor, the first bearingincluding first rolling elements; a second bearing located along theaxis and spaced apart from the first bearing, the second bearingincluding second rolling elements; a fixed shell enclosing the firstbearing, the fixed shell being configured to couple to an aerial vehiclearm; a rotor; and a rotatable shell enclosing the second bearing, therotatable shell being connected to the rotor by a rotor screw thatallows the rotatable shell to rotate about the second bearing.
 18. Theaerial vehicle motor of claim 17, wherein respective radii of the secondrolling elements are larger than respective radii of the first rollingelements.
 19. The aerial vehicle motor of claim 18, further comprising:a mount, wherein the fixed shell is configured to couple to the mountvia a screw through a bottom surface of the fixed shell.
 20. An aerialvehicle comprising: a motor system, the motor system including: a rotor,a mount extending along an axis and having a terminal end at an end ofthe mount, and a stator extending along the axis, wherein at least aportion of the stator is coaxial with the terminal end of the mount; afirst bearing directly coupled to the rotor and directly coupled to thestator so that the rotor is movable relative to the stator, wherein thefirst bearing includes an inner race, an outer race, and first rollingelements located between the inner race and the outer race; a secondbearing directly coupled to the rotor and directly coupled to the mountso that the rotor is movable relative to the mount, wherein the secondbearing includes second rolling elements, and wherein respective radiiof the second rolling elements are larger than respective radii of thefirst rolling elements; a top shell enclosing the first bearing, the topshell being configured to couple to an aerial vehicle arm at a firstside and being configured to couple to the mount at a second sideopposite the first side; and a bottom shell enclosing the secondbearing, the bottom shell being configured to couple to the rotor,wherein the terminal end of the mount terminates at the first bearing.